It is expected that environmental conditions impact the distribution of galls on host plants. Moreover, insects may induce their galls randomly or choose certain parts of a host to induce such growths. This study aimed to determine whether or not the gall midge, Hartigiola annulipes (Diptera: Cecidomyiidae), which induces galls on leaves of the European beech (Fagus sylvatica), prefers leaves facing a particular cardinal direction. In addition, we wanted to ascertain whether the galls are evenly spread across three leaf zones: proximal, median and distal, distinguished by dividing leaf area along the midrib. The results show that H. annulipes chose leaves facing various directions in different studied locations, and leaf choice is not restricted to the specific leaf area, a parameter that accurately reflects the light conditions of leaf growth. Moreover, the medial leaf zone was preferred, while the distal zone was avoided. The choice of the leaf zone modified the distance between the mid-rib and a gall. Gall distribution in the crown of trees is probably random, while at the leaf level, it is determined by leaf morphology., Sebastian Pilichowski, Marian J. Giertych., and Obsahuje bibliografii
Alien phytophagous insects are often introduced along with their host plants, creating opportunities for troublesome invasions. Yet, not all of them are able to successfully colonize novel host plants. In this study, we investigated host selection by the alien leaf miner Phyllonorycter leucographella (Zeller, 1850) on both its original host and novel host plants in the insect's alien range. We predicted that this insect's percentage infestation of the original host would be positively related to its specific leaf area (SLA), because high-SLA leaves are nutritious and have thin cuticles, traits related to high offspring developmental success. We further hypothesized that this host selection process would apply in the selection of novel host plants. Our results show that this leaf miner selects leaves of its original host plant, Pyracantha coccinea, according to their SLA values. The SLA value was also positively related to the probability of P. leucographella infesting and successfully developing on novel host plants. The selection of high-SLA plants by the moth leads to a high developmental success on novel host plants in the first (summer) generation, but it is likely to be maladaptive in the second (overwintering) generation, because in temperate Europe, high SLA values are associated with deciduous plants that shed their leaves in autumn. It is likely that the apparent maladaptive selection of novel host plants by P. leucographella reduces the invasiveness of this pest by preventing its establishment on native plants., Urszula Walczak, Michał Bogdziewicz, Roma Żytkowiak, Piotr Karolewski, Edward Baraniak., and Obsahuje bibliografii
Specific leaf area (SLA) is a key trait to screen plants for ecological performance and productivity; however, the relationship between SLA and photosynthesis is not always up-scalable to growth when comparing multiple species with different life cycles. We explored leaf anatomy in annual and perennial species of Physaria, and related it to photosynthesis and water loss. The annual Physaria gracilis had higher SLA, thinner leaves, and lower investment in protective tissues, than perennial P. mendocina. Physaria angustifolia (annual), and P. pinetorum (perennial) showed intermediate values. Both perennials had a thicker palisade and high photosynthesis, relative to annuals. The larger leaf veins of perennials should allow high water availability to the mesophyll. The thicker palisade should determine high resistance to water flow and help explain their high water-use efficiency. These leaf functions reflect the construction of long-lived leaves that efficiently use resources under environmental limitations of arid environments., L. Gonzalez-Paleo, D. A. Ravetta., and Obsahuje bibliografii
Seedling recruitment is a critical developmental stage in regeneration of plant populations under Mediterranean conditions that strongly depends on water availability. Seed mass and relative growth rate (RGR) may affect the early establishment of seedlings through different physiological processes. Here, we examined the effects of the seed mass and carbon balance on seedling growth under two water regimes in Rhamnus alaternus L. and Rhamnus ludovici-salvatoris, two Mediterranean shrubs, showing a different ability to recruit seedlings. Plant water consumption and biomass accumulation (ΔB) were measured during three periods of the growth in order to estimate water use efficiency (WUE), RGR, and its components. Additionally, net photosynthesis and leaf, stem, and root respiration were measured in plants grown in pots well watered and under progressive drought. Rhamnus alaternus showed the higher seed mass, ΔB, and plant WUE than that of R. ludovici-salvatoris in all periods and water regimes. The higher RGR of R. alaternus was observed during the first and the second period, but the reverse trend was registered during the third period as a consequence of the higher initial biomass of R. alaternus. Also, R. alaternus showed a higher specific leaf area and estimated carbon balance than that of R. ludovicisalvatoris. The observed differences in ΔB, estimated carbon balance, seed mass, and WUE between both species could explain their different distribution and ability to recruit seedlings under natural conditions., H. El Aou-Ouad, I. Florez-Sarasa, M. Ribas-Carbó, J. Flexas, H. Medrano, J. Gulías., and Obsahuje seznam literatury